The problems of cost control in the development process of the construction industry are endless, and cost control, as a core task in the process of project management, has a decisive role in the realization of project economic benefits. This paper combines the DEMATEL method and WBS work breakdown structure to screen and decompose the factors affecting cost under the cost control theory. Then, BIM5D technology is introduced to construct a refined cost control model based on the combination of the earned value method and BIM technology, in which the BIM-5D model can become its grassroots database and combined with the earned value method to provide the basic data for cost monitoring, cost early warning, cost correction and cost prediction, to realize an effective and refined control of costs. The case study shows that enterprise infrastructure, human resource management, internal logistics, procurement and bidding, cooperative and competitive relationships, technology development, project construction, completion and acceptance, and subsequent maintenance services all affect civil engineering costs. The control method can effectively control the construction progress and cost status, can play a good effect on the schedule-cost synergistic control, and provide support for the project management decisions of the constructor in the construction stage.